The proposed meeting combines and continues two series of meetings which were initiated in 1968 and that have taken place during the last 10 years. The first is the Jerusalem symposium which started in 1968 with a meeting on the Mechanism of Chemical Carcinogenesis. Subsequent annual meetings in Jerusalem have related to Quantum Chemistry and Quantum Biology. The carcinogenesis area was subsequently dealt with in 1972 at Johns Hopkins with a World Symposium on Chemical Carcinogenesis, and in 1977 with a symposium of Polycyclic Hydrocarbons and Cancer. The goal of the proposed meeting is to bring together leading scientists from around the world to discuss chemical carcinogenesis from both the mechanism and environmental viewpoints. The environmental aspect will include experts in polycyclic hydrocarbons, nitrosamines, aromatic amines and natural occurring carcinogens. The mechanism aspect brings experts in the field of theoretical and organic chemistry, and structure activity relationships, carcinogen metabolism, and carcinogen-macromolecule interaction. The experts in the biological mechanism of carcinogenesis include those related to mutation, human cell transformation, and possible relationship to viral carcinogenesis, genetic factors, and DNA repair related to carcinogenesis. With the broad scope of the meeting, the participants will be able to develop an overview of the major advances in carcinogenesis research that have developed in the last five years. A major component of the symposium will be the participation of prominent scientists who have been instrumental in the development of new methods and techniques in molecular biology and cell biology that may have particular relevance to carcinogenesis research. These individuals will be asked to stress in their presentations the usefulness of these new techniques in carcinogenesis related studies. These new developments include monoclonal antibody application, gene and chromatin transfer, somatic cell hybrids and recombinant DNA cloning techniques. Thus, we hope to bring together informational interaction that will significantly promote an understanding of mechanisms of chemical carcinogenesis and in particular the relevance of these mechanisms to environmental carcinogenesis.